Question

I’m writing a cron to backup some stuffs on a server.
Basically I’m sending specific files form a local directory using scp.
I’m using a public key to avoid authentication.

For reusability I’m passing the local directory and the server url by arguments to my bash script.

How I set my parameters:

#!/bin/bash

DIR="$1"
URL="$2"
FILES="$DIR*.ext"

My problem is about formatting the url.

Without formatting

How I send files to the server:

#!/bin/bash

for F in $FILEs
do
    scp $F $URL;

    if ssh $URL stat $(basename "$F")
    then
        rm $F
    else 
        echo "Fails to copy $F to $URL"
    fi
done

If I try to copy at user’s home on the server I do:

$ ~/backup /path/to/local/folder/ [e-mail]:

If I try to copy at a specific directory on the server I do:

$ ~/backup /path/to/local/folder/ [e-mail]:/path/to/remote/folder/

In all cases it gives me the well known error (and my custom echo):

ssh: Could not resolve hostname [e-mail]: nodename nor [...]
Can't upload /path/to/local/folder/file.ext to [e-mail]

And it works anyway (the file is copied). But that’s not a solution, cause as scp fails (seems to), the file is never deleted.

With formatting

I tried sending files using this method:

#!/bin/bash

for F in $FILES
do
    scp $F "$URL:"
done

I no longer get an error, and it works for copying at user’s home directory then deleting the local file:

$ ~/backup /path/to/local/folder/ [e-mail]

But, of course, sending to a specific directory don’t work at all.

Finally

So I think that my first method is more appropriate, but how can I get rid of that error?

Answer 1

Your mistake is that you can scp to [e-mail]: but not ssh to it : you need to remove the trailing : character (and possible path after it). You can do it easily like this with bash parameter expansion :

ssh "${URL%:*}" stat "$(basename "$F")"

RECOMMENDATIONS

• “USE MORE QUOTES!” They are vital. Also, learn the difference between ‘ and ” and `. See http://mywiki.wooledge.org/Quotes and http://wiki.bash-hackers.org/syntax/words
• if you have spaces in filenames, your code will breaks things up. Better use while IFS= read -r line; do #stuff with $line; done < file.txt
• See bash parameter expansion